I was driving the kids to the movies tonight and as I got to the turn, my hummer started idling really rough, then bucking a bit and stalling. The tachometer was racing without me touching the gas pedal and was going all the way up to three, then down to one, then up to two, very erratic. The check engine light then went on. It restarted right away and I backed it up and turned it around and parked it. After I put it back in drive from reverse, it appeared to be working normally. I parked and called OnStar who gave me info about a dealership nearby and I went into the movies with the kids. When I came out and started the car, it started right up and the check engine light went off as normal. I drove it home with no issues though it appears to be running a bit rough.

I did have the problem everyone had with the head (valve??) and it was repaired a few months ago.

My questions are (1) does anyone have any idea what this might be related to and (2) has anyone had this issue?

The nearest dealership is 60(!) miles away from our beach home and I'm hoping to find an authorized dealership on the Cape rather than have to go into Norwood.